In efforts to save space and weight in power split transmissions, some ball ramps have been made of formed sheet steel. Ball ramps typically experience axial loads which can deform sheet steel ramps. Axial support is therefore needed in the form of an axial or thrust bearing.
Sheet steel ball ramps typically do not provide a suitable bearing support surface for the applied axial load. Current solutions include using a U-shaped bridge adjacent to the ball ramp to act as a bearing surface which requires increased axial space or using an axial bearing at a different pitch radius than the ball ramp which leads to uneven loading.
Accordingly, a need exists for a ball ramp that overcomes the deficiencies of current ball ramps.